UFC Mexico City lost a fight but somehow ended up finding a storyline. Sofia Montenegro, the Season 9 Contender Series contract winner, was scheduled to make her long-awaited Octagon debut on February 28, 2026, at Arena CDMX. But with only a few days to go, she withdrew for unclear reasons, leaving Ernesta Kareckaite without an opponent.
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However, the chaos did not continue very long. Regina Tarin, an undefeated 21-year-old, steps in on just three days’ notice to make her UFC debut in a 130-pound catchweight bout in her hometown. And if you haven’t heard of her yet, that might change very soon.
Is Regina Tarin Mexican? Nationality, Ethnicity & Religion
Regina Tarin Malpica Rivera is a proud Mexican. She was born on October 19, 2004, in Mexico City (Distrito Federal), and she fights tirelessly to represent her hometown. A hometown debut in Arena CDMX? That’s not just any booking. That’s a moment.
Ethnically, ‘Kill Bill’ is simply described as Mexican, which points to Latin American heritage. Tarin’s family’s deeper ancestry is not well documented in public sources, and she has not made it a part of her public identity. What is evident, however, is that she brings her Mexico City toughness and pride into the cage.
Regarding religion, there is no confirmed public information. Regina Tarin has not discussed her faith in interviews, and major MMA databases show no religious affiliation. So, for the time being, that aspect of her life will remain secret, and that’s completely fair.
Regina Tarin’s MMA career that comes with a WWE twist
‘Kill Bill’ became pro in December 2023 and hasn’t lost since. She’s 7-0 with an 84 percent finish rate, including four knockouts, two submissions, and one fight that went the distance. That’s not just undefeated, but violent consistency.
Regina Tarin originally gained momentum fighting in regional promotions such as Budo Sento Championship, where she became the inaugural women’s bantamweight champion. Then came Combate Global, where she really gained attention. One of her biggest wins came against former The Ultimate Fighter contestant Kaytlin Neil, which quickly added credibility to her résumé.
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She was even scheduled for Dana White‘s Contender Series in 2025 but had to withdraw, a setback that could’ve delayed her UFC entry. Instead, fate circled back in a strange fashion. ‘Kill Bill,’ who was already set to compete in a Muay Thai bout in Mexico City this weekend, was asked to step into the Octagon on three days’ notice. Less chaos equals more opportunity. And here’s when things get interesting.
Regina Tarin reportedly tried out for the WWE at the Orlando Performance Center in January 2026. She trained, impressed the trainers, and was invited back. But she did not sign. Instead of moving to pro wrestling, she paused, thought it out, and remained focused on MMA. Right now, it appears that decision was pretty smart.
Instead of walking down a WWE ramp, she’s entering the UFC unbeaten, at home, and with a strong momentum. Whether this short-notice debut is a breakout moment or simply the beginning, one thing is certain: Regina Tarin is not just a substitute fighter. ‘Kill Bill’ might be the story of the night.